> Welcome to Cost+ developer documentation Cost+ is a modern payment processing platform that enables merchants to accept payments across multiple channels with transparent, cost-plus pricing. This documentation covers everything you need to integrate with the Cost+ API. ## API Base URL | | URL | |---|---| | **API** | `https://api.costplus.online/v1` | > [!NOTE] > There is no separate sandbox URL. Cost+ uses a single API endpoint. Whether a transaction is processed in sandbox or production mode is determined by your **API key** — specifically whether the website (project) in the [Merchant Portal](https://dashboard.costplus.io/) is configured as sandbox or production. ## Security All API requests are secured with **HTTP Basic Authentication**. You must connect over **TLS 1.2 or higher**. ```bash title="Example request" curl -u YOUR_API_KEY: https://api.costplus.online/v1/orders/ ``` ## Quick Links - **[Quickstart](/docs/getting-started/quickstart)** — Accept your first payment in 5 minutes. - **[Authentication](/docs/getting-started/authentication)** — Set up API credentials and learn how auth works. - **[Testing Your Integration](/docs/getting-started/testing)** — Test cards, sandbox environment, and going live. - **[FAQ & Troubleshooting](/docs/getting-started/faq)** — Common issues and how to resolve them. - **[Guides](/docs/guides)** — Step-by-step walkthroughs for common integration patterns. - **[Payment Methods](/docs/payment-methods)** — Supported payment methods and configuration. - **[SDKs](/docs/sdks)** — Official libraries for Node.js, Python, PHP, Java/Kotlin, C#/.NET, and Ruby. - **[Plugins & Integrations](/docs/plugins)** — Pre-built plugins for popular platforms.